Lifepo4 charger

[Guest]

We have 4 lead acid batteries on our narrowboat(new) and 600w of solar. Now it's getting colder and not as much solar our webasto doesn't kick in if around 12.2 ish. 

So can I get a separate battery ( lifepo4?) And charge this with a battery charger via the 240v socket while running the engine when moving? What amp's would that charger draw? And easier than rigging this battery up to the alternator charge side maybe. Thanks 

[sunny]

Join the 12 volt boating group on facebook read the files on hybrid battery set up

[Alan de Enfield]

2 minutes ago, Webomender said:

We have 4 lead acid batteries on our narrowboat(new) and 600w of solar. Now it's getting colder and not as much solar our webasto doesn't kick in if around 12.2 ish. 

So can I get a separate battery ( lifepo4?) And charge this with a battery charger via the 240v socket while running the engine when moving? What amp's would that charger draw? And easier than rigging this battery up to the alternator charge side maybe. Thanks 

 

 

That does seem immensely complicated and wastefull with all the inefficiencies at each stage.

 

Running the engine and using the alternator to generate 12v DC

Taking that 12v and using the inverter to convert it to 230v Ac

Taking that 230v AC and converting it to 12v DC via battery charger.

Using that 12v DC to power the Webasto.

[Guest]

Fully aware of that ,but the inverter is on all the time anyway so we thought plug a battery charger in. I don't have Facebook but I'll research thanks 

Edited September 17, 2022 by Webomender

[MtB]

15 minutes ago, Webomender said:

Fully aware of that ,but the inverter is on all the time anyway so we thought plug a battery charger in. I don't have Facebook but I'll research thanks 

 

Your proposal seems a bit clumsy but I think it will work, while your current set-up presumably doesn't.

 

Might be better to work out why your existing domestic bank isn't above 12.2v all the time. It ought to be, and the fact that it isn't suggests you are slowly killing it. 

 

Don't even think about LiFePO4 batteries until you have a thorough grasp of how to manage your lead acids. Learn the basics in our "Battery Primer" here: 

https://www.canalworld.net/forums/index.php?/topic/95003-battery-charging-primer/#comment-2100390

 

[Guest]

Hia thanks for your reply. When we switch off the engine 20.00 we're fully charged 12.7 on our readouts. But we work through the night so lights, lap tops and webasto etc. Time for bed we're then down to 12.2 ish. Webasto won't always kick in. I then don't won't to get up and start the engine so...thought of a webasto only battery. 

[Alan de Enfield]

28 minutes ago, Webomender said:

Hia thanks for your reply. When we switch off the engine 20.00 we're fully charged 12.7 on our readouts. But we work through the night so lights, lap tops and webasto etc. Time for bed we're then down to 12.2 ish. Webasto won't always kick in. I then don't won't to get up and start the engine so...thought of a webasto only battery. 

 

So you are at 12.7v at 8pm but by the time you go to bed you are at 12.2v suggests that either you are taking 'way to much out' of the batteries or they are 'goosed' and no longer have the capacity you think they have.

[Guest]

We work through the night draining them..printer's etc just stuff we use..

 

They are not just sat and drain to 12.2..we work. There new batteries only a problem as webasto needs to start up.. we draw power through the night

Advice would be lovely!! Forget it. Thanks anyway 

[GUMPY]

Get a better source of heating, solid fuel or diesel stove. The webasto problem then goes away. 🤭

[Guest]

At last constructive feedback 😀 

[Alan de Enfield]

15 minutes ago, Webomender said:

Advice would be lovely!!

 

If you are flattening the batteries with just a few hours working overnight then :

 

1) You need a bigger battery bank and the means to charge it fully.

 

2) If you are stopping charging when your battery is showing 12.7 volts then you are undercharging it.

 

3) New batteries can be killed in a matter of weeks.

 

4) A typical rule of thumb for battery bank size is 3x your daily consumption - have you actually done a power audit ?

 

Edited September 17, 2022 by Alan de Enfield

[Guest]

Who said a few hours work?

21.00to 0700 is not a few hours and both working.

[MtB]

2 minutes ago, Webomender said:

Who said a few hours work?

21.00to 0700 is not a few hours and both working.

 

In that case I think a separate battery bank specifically for the Webby is a Good Idea. 

[Guest]

Thankyou, you and me are on the same page here. Any ideas how please.?

I know our battery set up is new and at its optimum ( set up correctly by a well known fella) we have done the power audit but have had the webasto fitted after.

[George and Dragon]

8 minutes ago, Webomender said:

Who said a few hours work?

21.00to 0700 is not a few hours and both working.

Alan's rather brusque point about the power audit is worth considering. If your batteries are down to 12.2 (fully discharged) by bedtime then you may need a bigger bank.

2 minutes ago, Webomender said:

I know our battery set up is new and at its optimum ( set up correctly by a well known fella) we have done the power audit but have had the webasto fitted after.

If it's fully charged at the end of a day's cruising...

[MtB]

10 minutes ago, Webomender said:

Thankyou, you and me are on the same page here. Any ideas how please.?

I know our battery set up is new and at its optimum ( set up correctly by a well known fella) we have done the power audit but have had the webasto fitted after.

 

Its quite difficult to advise without a clear understanding of what you have now and how you are using it. What size domestic battery bank do you have, what alternator and what is your charging regime in detail, please?

 

The solar is approaching the end of its summer usefulness and you are soon going to be 100% reliant on other ways of charging. If your charging capability is insufficient for your energy consumption, it will make no difference how you share it out amongst battery banks. I'm concerned because in my experience, heavy use of computers is an absolute battery killer. 

 

Could you post up your power audit perhaps? 

[Tony Brooks]

Once again and I am so fed up i will shout - YOU CAN NOT DEDUCE THE STATE OF CHARGE OF A BATTERY UNDER CHARGE BY VOLTAGE. The only way with lead acids is to watch the charging current.  This means that your statement about the batteries being fully charged at 12.7 volts is just plain worn and as Alan says you are just ruining them.

 

12.7 to 12.8V RESTED voltage will indicate a more or less fully charged battery as long as you know what RESTED VOLTAGE means.

 

Most alternator regulators regulate at around 14.4 volts these days so at 12.7 V charging voltage mesas the battery is maybe less than 3/4 charged and there will still be a high charging current flowing.

 

Also, a Webasto set up as a marine unit (rather than automotive) should start at a lower voltage than 12.3v, after all at 12.2 volts RESTED voltage the battery is still about half charged (but at its maximum discharge level for optimum life).  Can you confirm this really is a marine unit and have you measured the voltage AT THE WEBASTO when trying to start it? I would want to rule out volt d op between the batteries and the unit.

 

I think you need to clarify just how much you know or do not know about LA batteries and their charging, plus give us the voltage at the batteries AND the Webasto when it refuses to start before we can start to advise. I think your plan may work, but it is only covering up and existing problem, be it an actual fault or just good old user error. At present, I suspect the latter.

 

Edited to add: PS - Your statement about 12.7V when switching the engine off makes me suspect that you are not measuring the rested voltage but are measuring the surface charge on the plates. If so you probably have several hours to go to get fully charged and that surface charge will drop quickly as soon as you start to discharge the batteries.

 

It may also help if you post your power audit and the charging calculations you used. As Alan said (and which you did not seem to like), if your power audit is correct then you may have already destroyed a lot of battery capacity OR the bank is no longer large enough to support the loads.

Edited September 17, 2022 by Tony Brooks

[Guest]

Time to leave this site. Don't know who you think you are but you dont shout at anyone , period... don't reply if it winds you up.. shout!!

[Tony1]

 

I hope you wont be put off by the odd rather brusque comment, in fairness these people are very very knowledgeable, but they do get asked the same question almost on a daily basis, and there are a few basics its important for them to know in order to help properly. 

 

I remember I had a similar problem when I first got my boat- I would cruise all day (plus 660 watts of solar panels), and the batteries would appear to be brim full, but by 11pm they would be down to 12.2, and I'd be wondering if the diesel CH was going to come on in the morning. 

If you are serious electrical users you have to be looking at some lithium batteries to help out, they really are a game changer.

 

There is one piece of advice above that I would also strongly reiterate. If you haven't already, get a solid fuel stove installed asap. 

I got my boat in August and by late Oct, the CH just wasnt enough. I was running it for half the day (which now will cost a lot more for diesel), and I had condensation every morning. 

I had a SF stove put in by mid-November, and the transformation was instant and amazing.

The boat was suddenly really warm, but also with a dry heat, so no condensation, and was a much more pleasant environment to live in. At no point during the night was the temp inside fall below about 15 degrees, and in the mornings the stove could be brought back to full life with a few minutes minor effort. 

Coal is a hassle and a bit messy, but it transformed my boat, and I wouldn't even contemplate being on a boat in winter without a SF stove. 

Apologies if you've got one and just not mentioned it, but if you haven't, you need to give it some serious thought asap. 

 

 

 

[Guest]

Thanks. 

[ditchcrawler]

3 minutes ago, Webomender said:

Thanks. 

I think you need to realise the difference between shouting (I assume you mean using capitals) and emphasising the important bits. I do wonder if you work from 9 at night until 7 in the morning when you charge your batteries. You could do what you propose with a split charge relay to charge your Lithium but that will only work if you run the engine long enough to recharge both that and your depleted Lead Acid. 

[Tony Brooks]

3 minutes ago, Webomender said:

Time to leave this site. Don't know who you think you are but you dont shout at anyone , period... don't reply if it winds you up.. shout!!

 

By all means do so. If you want a private reply just dedicated to you then either PM whoever you think can help or pay for professional help.

 

My reply is for all who may read it, either now or in the future and as such certain things need to be emphasized. One of which is your assertion that 12.7V = fully charged. It does not apart from in a specific circumstance and after a following a procedure.

 

From your series of posts it looks very much as if you do not understand what you are dealing with, but that is fine by me, if I am correct then you will just carry on ruining your domestic bank, and I want to prevent others doing the same. If I am wrong then fit your extra battery, and it will appear to work.

 

 

[Alan de Enfield]

29 minutes ago, Webomender said:

Time to leave this site. Don't know who you think you are but you dont shout at anyone , period... don't reply if it winds you up.. shout!!

 

How sad - it appears that you cannot accept reality and if you are told something you don't want to hear, you shoot the messenger.

 

 

Edited September 17, 2022 by Alan de Enfield

[system 4-50]

36 minutes ago, Alan de Enfield said:

How sad - it appears that you cannot accept reality and if you are told something you don't want to hear, you shoot the messenger.

Have a go at composing a post that reassures Webomender that, no offense was intended by any post and, accepts TB's need to not leave any posts around that may mislead future forum dipper-iners.  Your dog post is funny but is not going to help, is it? We can play nicely if we want to, can't we?

[Alan de Enfield]

2 minutes ago, system 4-50 said:

We can play nicely if we want to, can't we?

 

 

Of course we can but when you post possible reasons for his voltage problems and you get ..................

 

 

5 hours ago, Webomender said:

Advice would be lovely!! Forget it. Thanks anyway

 

 

I stand by the ............................

 

 

46 minutes ago, Alan de Enfield said:

it appears that you cannot accept reality and if you are told something you don't want to hear, you shoot the messenger.

 

 

And then TB post clearly and concisely how he views the OPs problem and gets .................................

 

 

1 hour ago, Webomender said:

Don't know who you think you are but you dont shout at anyone , period...

 

We can do without posters that if they are not told how wonderful their ideas are start to get aggressive.

 

The OP can wire up his batteries how he wants, its his boat, his batteries and his life.

 

"I'm out"